Methods for determining the hematocrit value HKT of blood are known. One known method for determining the hematocrit value is based on an electrical conductance measurement, wherein the measured conductance is inversely proportional to the hematocrit. Such methods are described, for example, in “Labor und Diagnose” by Lothar Thomas, TH-Books, 5th volume, 1998, and K. Dörner, “Klinische Chemie und Hämatologie”, Georg Thieme Verlag, Stuttgart, Germany, 1998, 2003. Moreover, products for hematocrit determination using electrical conductance measurement were offered by iSTAT Corporation, East Windsor, N.J., USA (http://www.istat.com) at the time of application.
A further method for determining the hematocrit value is referred to as micro-hematocrit method. Here, a micro-capillary having an internal diameter of 1 mm is dipped into the blood to be measured. The blood rises in the capillary, driven by the capillary force. This is now sealed at one end and inserted into a micro-hematocrit centrifuge or a microhematocrit rotor, and centrifuged according to the NCCLS standard. The determination of the hematocrit value HKT takes place either by a measurement disk or a measurement assembly. Direct readout of the hematocrit value is possible still in the centrifuge with the measurement disk. The great disadvantage of this method is the necessary manual sealing of the capillary.
The micro-hematocrit method is approved as a reference method, wherein the values obtained are up to about 2% higher than the comparative measurements with a hematology analyzer, due to the enclosed plasma. With respect to this micro-hematocrit method, for example, reference may be made to K. Dörner, Klinische Chemie und Hämatologie, Georg Thieme Verlag, Stuttgart, Germany, 1998, 2003, or B. Bull et al., Pennsylvania, USA, ISBN 1-56238-413-9 (1994). Furthermore, this technology is practiced by the company Hermle Labortechnik GmbH at the time of application (http://www.hermle-labortechnik.de).
Methods for filling blind channels, i.e. channels with one closed end, which are supposed to prevent enclosure of bubbles, are known. Such methods are described, for example, in Steinert C P Sandmeier H, Daub M., de Heij B., Zengerle R. (2004), Bubble free priming of blind channels, in Proceedings of IEEE-MEMS, Jan. 25-29, 2004, Maastricht, The Netherlands, p. 224-228; and Goldschmidtboeing F., Woias P. (2005), Strategies for Void-free Liquid-filling of Micro Cavities, in Proceedings of Transducers '05 Conference, June 5-9, Seoul, Korea, ISBN 07-7803-8994-8, p. 1561-1564; as well as in DE 10325110 B3.